How often calibrate refractometer?

[number1gsxxr]

Like the title says, how often should you calibrate your refractometer?

 

[stingythingy45]

I did mine once.
But that's just me.

 

[jbishop]

Once here also.

 

[MPS]

I find I have to calibrate about once a week. It always shows a slight shift upwards. I use a 53mS cal fluid its cheap and will last a long time.

 

[sixspeed]

I have only calibrated mine once, but i think i should check it again. After all calibrating takes all of 2 minutes.

 

[stingythingy45]

I think I'd only double check it if I were going to do hyposalinty treatment.

 

[Mini4x]

you're supposed to do that??

OOPS.

 

[afboundguy]

I've never checked mine in 5+ years but I've thought about it if that counts for anything

 

[stevenp]

I check mine all the time with ro or tap water (both will read 0.00sg) and adjust as needed. Sometimes it's off just a hair and sometimes it's exact.

I'm always surprised how few people check theirs as it's so easy to keep them in tune. I've purchased livestock and corals countless times from other members who's salinity was off the charts when I checked it before starting acclimation. In most cases they had no clue because their refractometer wasn't calibrated.

 

[smartfish]

I find it is a good idea to check at least once a month.

 

[Miller]

I check our a few times a month, its quick and simple so why not.

 

[Glenn E King]

Calibrating

There was an article somewhere ( Advanced aquarist? ) that recommended against using RO water to calibrate.

Anyone know why?

 

[justintrask]

I'm not sure what we use to calibrate, but we tend to calibrate ours once a month at the shop.

 

[coralcor]

i still dont own one....

 

[paulthomas]

There was an article somewhere ( Advanced aquarist? ) that recommended against using RO water to calibrate.

Anyone know why?

My FIL uses refractometers to measure dog, cat, etc. urine and told me to use some solution and not tap or even RO(DI) water. He said it doesn't recalibrate properly. He didn't have time to go into a reason why.

I'm guessing MPS is right with the 53mS Cal fluid.

I calibrate with RO every time I use it.

 

[crb]

I just bought some distilled water and used that for calibration when I got the thing about a year ago. Haven't tested it since so I just did it again (with the same water) and it is exactly where I set it a year ago.

 

[paulthomas]

I just bought some distilled water and used that for calibration when I got the thing about a year ago. Haven't tested it since so I just did it again (with the same water) and it is exactly where I set it a year ago.

Well you're refractometer calibrates consistently wrong, Carl!

 

[sciknen]

i calibrate with distilled water..just did mine.it was .04 off lol that couldve been bad

 

[crb]

Thanks for your concern Paul
RO/DI water also reads 1.000 SG

 

[Kevin McG]

About every 6 month with some distilled water.